172RG hydraulic system

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I am starting to fly in a 1980 172RG Cutlass after doing a lot of training in an Arrow II. The hydraulic system for the landing gear seems to be a little different than on the Arrow (not a lot exposed, so I can't really get a good picture of whats going on) Does anyone have any good photos or graphics of the inner workings? The POH doesn't shed much light either. Thanks!
 
Have you tried talking to the mechanic who works on the rg. He/She could show you the maintenance manuals...they have some good diagrams.
Happy Landings
 
Its really simple. Hydraulic pressure is maintained at 1500psi and a switch turns the pump on at 1000psi (I think, it's been a while). All the gear lever does it change the fluids direction. The only squat switch is in the nose gear, so be carefull when moving the airplane with the master on. There has been more than one pilot who's gear has started to retract while on the ground.

You can pump the gear up, but I wouldn't. I'd rather have them stuck down. There are no up-locks, so if you hear the pump cycling more than a few time's in flight, lower the gear and leave them down, you could have a fluid leak and if it all leaks out, you gear won't come down all the way.

I think that covers it. Did I miss anything?
 
mshunter said:
Its really simple. Hydraulic pressure is maintained at 1500psi and a switch turns the pump on at 1000psi (I think, it's been a while). All the gear lever does it change the fluids direction. The only squat switch is in the nose gear, so be carefull when moving the airplane with the master on. There has been more than one pilot who's gear has started to retract while on the ground.

You can pump the gear up, but I wouldn't. I'd rather have them stuck down. There are no up-locks, so if you hear the pump cycling more than a few time's in flight, lower the gear and leave them down, you could have a fluid leak and if it all leaks out, you gear won't come down all the way.

I think that covers it. Did I miss anything?
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You can't pump the gear up. It is a directional pump. Plus, why would you want to do that?

Mainly, if anything goes wrong with the lines and you do lose fluid your in an ugly place. If I recall and it has been a while, I think there is a reservoir that holds enough oil for one extension just in case you get a leak somewhere in the main system but I could be wrong on that. I haven't flown a Cutlass in a year or so and I'm happy about that!
 
Codyjp said:
You can't pump the gear up. It is a directional pump. Plus, why would you want to do that?

Mainly, if anything goes wrong with the lines and you do lose fluid your in an ugly place. If I recall and it has been a while, I think there is a reservoir that holds enough oil for one extension just in case you get a leak somewhere in the main system but I could be wrong on that. I haven't flown a Cutlass in a year or so and I'm happy about that!
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Like I said, it's been a while. For some reason I remember another instructor saying something about pumping them up. But at any rate, I found a picture of the system. I don't think there is a separate reservoir. I can't find one in the diagram.

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mshunter said:
Like I said, it's been a while. For some reason I remember another instructor saying something about pumping them up. But at any rate, I found a picture of the system. I don't think there is a separate reservoir. I can't find one in the diagram.

7-28.jpg
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Yeah, were probably both equally unqualified to answer these questions... The one I used to fly needed to be geared in though. It was so close to death as it was somebody just needed to put it down!
 
The way I understand it is the reservoir is located with the power pack. It uses something akin to a standpipe to extract the fluid from the tank. Since that pipe does not go all the way to the bottom, there will be hydraulic fluid left in the line in the event of a leak in the system. If there is a leak the pressure in the lines will decrease and power pack will come on and continue to run until pressure is returned to 1500psi. Obviously if there is a leak in a line that pressure won't be reached and you will just keep pumping the fluid overboard.

The power pack will start sucking air before the fluid is depleted. The emergency hand pump utilizes that remaining fluid and it's own separate lines to lower the gear. I'm 90% sure the hand pump can not be used to raise the gear.

The gear is locked in the down position with hydraulically actuated mechanical locks, except the nose wheel which uses an over-center locking thingy. Locking the gear up is accomplished with nothing more than hydraulic pressure. In the event you lose that pressure the gear will dangle out the bottom of the aircraft.

As said earlier, the gear lever does nothing more than change the flow of the pressure. It does not activate the power pack. a psi in the lines below 1000 will activate the system and it will run till the gear has cycled AND the system re-pressurizes.

That's all I can think of at this late hour.
 
One last thing. Make sure you have a cane or something similar in the aircraft. That way you can pull the mains forward in case of a hydraulic fluid leak.

It would be worth the investment for the school considering a belly landing is a bit more expensive.
 
Maurus said:
One last thing. Make sure you have a cane or something similar in the aircraft. That way you can pull the mains forward in case of a hydraulic fluid leak.

It would be worth the investment for the school considering a belly landing is a bit more expensive.
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Have you tired this method before? I pretty sure it would be fairly difficult, even when slowing down to a slow speed. What about the nose gear?

That's what insurance is for. I am not risking my life by trying to pull both mains down.
 
Maurus said:
Do you not wear a seat belt? Anyway if you don't feel comfortable when you try, then don't do it.
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I've heard people suggest this as a means of pulling the gear down. has anyone actually tried thus method? How realistic is it?
 
poser765 said:
I've heard people suggest this as a means of pulling the gear down. has anyone actually tried thus method? How realistic is it?
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I haven't had any hydraulic problems personally, but my boss claims to have done it and he is not the type to embellish stuff to feel superior.
 
Maurus said:
I haven't had any hydraulic problems personally, but my boss claims to have done it and he is not the type to embellish stuff to feel superior.
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BS. I don't buy it for a second and to even attempt it is just stupid. I'm not paid nearly enough for fruitless stunts like that.

Now, it is was a P-51 or something, I'd probably crawl out onto the wing or something to save it because I couldn't live with myself if I ruined a classic!
 
Codyjp said:
BS. I don't buy it for a second and to even attempt it is just stupid. I'm not paid nearly enough for fruitless stunts like that.

Now, it is was a P-51 or something, I'd probably crawl out onto the wing or something to save it because I couldn't live with myself if I ruined a classic!
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It's been doen a few times.

From another forum

Here is his story offered without comment:

EMERGENCY PROCEDURES

A Saturday Flight Provides More Excitement Than Planned​
A pilot's success depends, among other things, on inventiveness. Navy pilots who must make it back to a ship before they can land have a phrase that says, "Never, never, never, never give up!" At this moment those words rang in my head.

It started as a normal checkout flight for any pilot in a new aircraft, except that this was also an interview of a candidate for a new flight instructor position with the company. As the company mechanic I had no business reason to go on this flight but I went along as an observer to watch my partner performing the interview and also just for a nice Saturday flight. We had the applicant, Scott, perform many maneuvers and we were proceeding to the emergency procedures phase of the flight. In a complex aircraft there a two types of failures that are easy to simulate. The first is an engine failure, where the instructor (my partner in this case) throttles the engine back to idle and tells the pilot, "Okay, your engine just died. What is the procedure?" The correct action includes maintaining the best airspeed for glide and finding a place to land and so on. The other failure is a landing gear pump failure that is simulated by pulling out the circuit breaker for the gear pump motor. The pilot must recognize that the wheels have not extended and then use the emergency extension pump which is a hand pump located in the floor between the two front seats.

I was enjoying the flight and didn't notice that my partner, Richard, had pulled the breaker for the gear pump. When Scott throttled back to descend the landing gear warning horn came on. He aborted the approach and started pumping the gear down by hand. This normally takes twenty to thirty pumps of the handle and there is considerable resistance as the gear is quite heavy. After about seven pumps, there was a loud clunk and the handle suddenly moved with no resistance at all.

We looked at each other as the control tower asked if we were coming around for another approach. We told them that we had some kind of malfunction and we were departing the area to figure it out. The first thing we tried was to re-raise the gear to see if it was stuck. Rich selected gear up and pushed in the circuit breaker for the main pump which then started to retract the gear. He again selected gear down and we could hear the electric pump freewheeling as the gear remained half way down.

I should take just a moment to explain the landing gear in this type of high-wing aircraft. In most low-wing aircraft the gear swings on a simple hinge into the wing and into the nose. In a high-wing aircraft this is impractical and so while the nose gear does swing forward into the nose, the main gear is different. In the normal 'down' position the gear is pointing out to the sides of the fuselage. During the first part of retraction, the gear swings DOWN so that it is hanging vertically from the fuselage and then swings up and aft into the rear of the belly. Extension is the opposite with gravity helping the gear swing down out of the belly and then hydraulic power to lift the gear out to the side of the plane. Once in place there are small hooks that are spring loaded and can hold the gear down and locked if the pressure bleeds down.

Richard turned to me and said, "Mechanic, fix plane. Now!" I couldn't tell what was wrong from the back seat so Scott, who had been sitting in the right seat crawled in back and I took his chair up front. The only tool I had available to me was actually the fuel sampler which has a screw driver tip on it. I began removing the shroud around the emergency pump handle so that I could see underneath the floor. There is about a seven inch space between the flat load floor and the rounded belly of the aircraft. In that space I saw about two inches of hydraulic fluid sloshing around. I reached down and felt the under side of the emergency pump to try to find a broken piece. My hand came back coated with red hydraulic fluid and I told my partner, "This is NOT good."

About now the control tower realized that we might need some help and asked the question no pilot wants to hear, "Sir could you tell us the number of souls on board and hours of fuel remaining?"

"Three on board and about five and a half hours of gas," we replied, as I began removing more pieces of the floor. I had Rich lift up his feet as I pulled out the carpeting and had Scott place it in the cargo compartment. With more of the inspection panels removed from the floor, I estimated that there was about a gallon of hydraulic fluid running around loose in the belly. Nearly the entire system capacity. I realized at that point that we had very few options. I radioed the tower and told them to have one of our employees call the other mechanic at home and have him drive to the airport and look at the schematics to see if there were any options I had missed.

Now we were waiting. Trying to make small talk and stay calm and keep our heads about us. The cabin door had not been fully closed prior to the flight and had been blowing cold air on me when I was in back. While I had the time I decided I'd try to close it a little better. As I popped the door open a bit to slam it, I noticed that I could see the main gear hanging almost straight down back there. Then it hit me! I had once read an article about a pilot who had lost all his hydraulic fluid and was able to pull the landing gear into place by hand! I had Rich crack his door open and see if the gear was visible on his side. It was. What we really needed to know now was if the nose gear had fallen into place by gravity and the slipstream blast alone.

We called the tower and requested a low pass for nose gear inspection. While approaching the airport we asked what altitude we could descend to. Tower replied, " Altitude at your discretion." We went right past the tower windows and the call came over the radio, "Your nose gear appears to be down." As we went by I noticed many fire trucks present on the ramp awaiting our arrival.

The other option I came up with was to rock the aircraft vertically to try to force the gear into place. Rich put the airplane into a steep climb and forced the nose down abruptly. All of the carpeting and inspection panels we had stowed in the back came flying up to the ceiling and I watched as the gear swung out and then back down to where it started.

The other mechanic made it to the tower and suggested that we try the electric pump again for ten seconds and if nothing happens then he agreed that my idea was our only choice. After listening to the pump whine for ten seconds with no results we knew we had only one option left if we were to preserve the smooth aluminum skin on the belly. I realized that the gear was too far aft to reach by hand and that I would need to use the aircraft towbar (stowed in the cargo compartment) as a hook to grab the gear leg. I told Rich to take us over an unpopulated area just in case I dropped the towbar. The right main gear was first.

Richard had slowed the airplane down as much as he safely dared and I had sinched up my lap belt since I couldn't move far enough with the shoulder harness buckled. I propped the right door open with my left knee and, with the towbar in a white knuckle grip in my right hand, reached back and down . It was difficult to snag the gear at first because even with the aircraft flying as slow as safely possible, there still is a nearly seventy mile per hour blast of air. After wobling around awkwardly for a few seconds I was able to hook the gear leg in the towbar pinchers.

With all of my strength I pulled on the gear and could not bring it into position so Scott, now sitting in the back seat, grabbed the towbar and with both of us straining we felt the gear touch the stop. When we let the towbar down the gear stayed in place! After a moment's celebration it was time to get the left gear down. Scott and I switched seats again so he was in the front right seat and I was in the rear while Rich flew the plane from the front left seat. Again we propped the door open and reached down and aft with the towbar to grab the gear leg, and again I alone was not strong enough to pull it into position so Scott grabbed the end of the towbar this time and shoved down, using the door sill as a lever point to wrench the gear against the stop.

"Green light! Green light! Gear is down!" shouted Rich as I brought the towbar back into the plane and closed the door. Now it was time to land. I warned Rich that the gear was only held in place by small hooks and the weight of the aircraft, once on the ground, would tend to keep the gear down. But, if we were to bounce on landing, the gear could be jolted off the hooks and collapse as we settle on it. Also, we could not be sure how well the nose gear had locked without any hydraulic pressure on the locks. So the landing had to be performed without any bounce and once down my partner could not use either the brakes nor the nosewheel steering for fear that the whole works might not be locked in place. If the nosewheel did collapse it would be preferable to not have the propellor turning when the nose hit the pavement, so we would have to shut down the engine while landing the plane to stop the propellor before the nose wheel touched down. Which meant that the first landing would be the only chance we got.

To make matters worse, the winds had picked up at the airport and it was blowing across the runway which makes it difficult to land without bouncing and almost impossible to stay on the runway without using the wheels for steering. Needless to say we all sinched down our seatbelts extra tight. From my seat in the back I could not see the runway during the landing, but instead I heard Rich and Scott talking over the headsets. We agreed that Rich would fly the approach while Scott read out the airspeed every few seconds and also was responsible for cutting the fuel to the engine after the main wheels hit but before the nose came down. So it went, as I watched the left main wheel out the side window and listened to the headset. "70 ... 75 ... 70 ... 70 ... 65 ... 70" As the runway came into view under the side of the plane I'm sure I was putting new button holes in the seat. One foot above the ground we decided we were committed to the landing just as a gust of wind let us drop onto the main wheels. Scott killed the engine and Rich pulled back all the way on the controls to keep the nose off until the prop stopped turning. I could see the prop windmilling slowly but not stopping. I quickly prayed stop, stop, oh please stop. I never even felt the nose wheel hit, a testament to Rich's skill. As we rolled to a stop the wind took us to the edge of the pavement but not into the grass.

I was the first one out so I checked the nose gear to see that it was secure. A truck had been dispatched to tow us in to the ramp but they were going to place a towbar on the nose and pull the airplane like they normally do. I said that we would hand push the plane to the ramp before I'd let them tug on that wheel so that's what we did. Richard and one of the ramp hands pushed on the right side while Scott and I pushed on the left. I noticed the paint around the doorsill was scratched where we had pried against it, "Aw man, we scratched the paint," I said.

"We would've scratched it a damn bit more if we hadn't gotten that wheel down," exclaimed Scott. I agreed. As we walked I asked him, "How do you feel?"

He thought for a moment and said, "You know, right now I feel pretty good."

End of Story
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I vaugley remember seeing a video of it a long long time ago.
 
I doubt it less, but I still see all sorts of problems with this. if you are hanging out the damn door with a cane trying to grapple the landing gear I would imagine you are not in fact flying the airplane. Single Pilot Resource Management goes out the window. Hmm, pun?
 
poser765 said:
I doubt it less, but I still see all sorts of problems with this. if you are hanging out the damn door with a cane trying to grapple the landing gear I would imagine you are not in fact flying the airplane. Single Pilot Resource Management goes out the window. Hmm, pun?
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Yeah, but with a team of people, like the quote has, it's possible. I remember hearing one guy talk about someone hanging onto his pants belt so he didn't end up falling out the airplane.
 
mshunter said:
7-28.jpg
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...and people wonder why Cessna doesn't make GA retracts anymore.
That looks exactly the same as the 182rg diagram.
I never had a problem and I never "worried" about it, but when compared to other GA retracts it is definitely on the weak side of things.

[YT]ZnToe7zOa8E[/YT]

A picture of solid reliability.

Edit: You know people don't really think of a Cessna as being sexy but a 182/210 do have some appeal when the swoop in for a low pass without gear.
 
The towbar or a cane around the mains does work but only do it if you have someone else who can fly while you pull... and try not to fall out of the airplane. ;)

You'll never get the nose gear out of the well ever.

Preflight the gear wells religiously in a retract cessna, any (and I mean any) hydraulic leak is a cause to not fly.
 
trafficinsight said:
You'll never get the nose gear out of the well ever.
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Why would you say that?

Is there an electric uplock on the nose? If so, it will probably work like the older C210s. The uplock is held electrically, if you remove power (turn off the master), the uplock fails open, and the gear will fall out, allowing the pump/air load to extend the gear.

I wouldn't recommend the "cane technique" based on the following considerations.
You are trying to pull the gear against the slipstream
You are pulling at an acute angle to the gear movement (gear trails down/behind.

This "technique" only works if the gear is fully extended, but not quite locked in position.
 
The 182 I worked on was a mechanical uplock and if there's no hydraulic pressure there's no releasing it

Sent from my Droid using Tapatalk
 
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